1. Field of the Invention
Embodiments relate to a compact wide-angle zoom lens and an image pickup device having the same.
2. Description of the Related Art
Currently, digital cameras or video cameras including a solid state imaging device such as a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) are popular. In particular, demand for mega-pixel camera modules is increasing and low-price digital cameras having high-pixel count and high-quality performance are being introduced. Optical devices using an imaging device such as a CCD or a CMOS, for example, digital cameras and mobile camera phones, require a compact, light and low-price zoom lens. Furthermore, demand for a wide-angle zoom lens is increasing, by which may capture a wide-angle image of a subject.
As a wide-angle zoom lens, a retrofocus-type lens including a front lens group having a negative refractive power and a rear lens group having a positive refractive power is commonly used. The retrofocus-type lens includes an asymmetric lens having a high negative refractive power and thus aberrations such as distortion and astigmatism may easily occur. In order to correct the aberrations, for example, an aspherical surface is used and thus the number of lenses is increased. Accordingly, a compact and low-price lens system may not be easily provided.
Also, when a retrofocus-type lens performs focusing from an infinite object distance to a short object distance, the height of a paraxial ray that is incident in a lens system greatly varies and thus the amount of aberration is increased. Thus, in a retrofocus-type lens, a method of correcting variations in aberration is regarded as a major issue.